The present invention relates to a new and improved arrangement for tension control and supervision of individual warp threads on a loom, particularly a circular loom.
More specifically, the invention relates to an arrangement for tension control and supervision of individual warp threads on a loom, particularly a circular loom, comprising a two-armed movable lever, which is swivel-supported on the loom and which is held by a warp thread, found in a stretched state and guided through a yarn guiding eyelet on the one movable lever arm, countering the effect of a spring means, which engages on the lever arm that is free of eyelet, and which is in a regulating position, which compensates the alternating tension on the warp thread, with the movable lever closing an electric circuit when brought into signal position as a result of the unstretched or missing warp thread.
With weaving looms, particularly circular looms, the formation of the shed leads to great changes in the tension on the warp threads, the compensation of which is absolutely essential. This compensation of tension poses a great problem, which has not been sufficiently solved with the means of the prior art until this present day.
With one such arrangement of the aforementioned kind, conventionally known in the art, by which two kinds of springs engage on the movable lever for the taking in of the changes of tension on the warp threads, these springs call for a moment of rotation which is dependent on the tension of the warp thread, running through the eyelet of the movable lever. One of these springs is arranged in such a way that it only comes into effect when the angle of rotation of the lever exceeds a permissible area. Moreover, the back side of the movable lever carries an electric-conducting coating, in order to bridge the contact of a switch when in one of its extreme positions with unstretched or missing warp thread.
Such an arrangement is, howeever, defective and unsuited in fulfilling the requirements of today. For example, the movable lever employed in accordance with the above-mentioned patent specification is relatively heavy, not least owing to its necessary stability for engaging two tension springs and the required electric coating. This, however, makes the lever sluggish, so that this only delays the change of tension--if it can ensue at all. Moreover, this known arrangement is very complicated, requires exact spring characteristics and a precise setting of the movable lever as regards the switch contact by which this is to be bridged. Both the installation and the replacement of the movable lever on the loom are exceptionally costly and time-consuming.